A Halo should spin if there are no paintballs detected (ie also when hopper is empty it spins and spins). The eyes (as I remember on my old Halo) should be taped around the inside of the upper feedneck portion. Perhaps they are bad?

I don't know if it is worth fixing the situation or not. Halo shells suck so badly that I would honestly buy a more modern and tool-less hopper.